Cellulose particulate material

ABSTRACT

The invention relates to plant-derived cellulose-containing particles useful as rheology modifiers and to a process for preparing cellulose-containing particles from plant material, which process involves treating said plant material with a peroxide reagent. The process can be controlled to produce cellulose-containing particle having a viscosity up to about 7500 or 8000 cps.

FIELD OF THE INVENTION

The present invention relates to a process for preparingcellulose-containing particles from plant material using a peroxidereagent, the particles, and compositions comprising the particles. Theprocess can be controlled to provide cellulose-containing particleshaving a viscosity in water falling within a wide range. Thecellulose-containing particles can be useful as rheology modifiers andstrengthening agents in water-based systems.

BACKGROUND TO THE INVENTION

Cellulose forms the basic structural component of plant cell walls whereit exists in the form of cellulose fibres. The use of celluloseextracted from plant material attracts interest because, generally, thecellulose has good strength, stiffness, biodegradability andrenewability properties. It is known to reinforce materials such asplastics materials and epoxy resins, with coarse plant fibres from hempand flax, for example. It is known to use chemically modified cellulose,such as hydroxyethyl cellulose, to increase the viscosity of an aqueousmedium such as an emulsion.

However, the production of such chemically modified cellulose is energyintensive, involving a number of treatment steps. Cellulose fibres canbe broken down to the substructures of microfibrils and nanofibrils.More recently, the use of these highly purified cellulose substructuresas additives for modifying the physical properties of a material hasattracted interest. In particular, it is known that some microfibrillarand nanofibrillar cellulose compositions can have a high viscosity inwater. Such high viscosity compositions could be, useful as viscositymodifiers.

The processing of untreated plant material to obtain microfibrillar andnanofibrillar cellulose compositions is also energy intensive andinvolves a number of stages including various chemical treatments andhomogenisation through, for example, shear mixing or high pressurerelease or through grinding, filtration and pressing. Generally, thelarger the number of process stages required, the more energy isrequired to produce the end product. There is a need for alternativeand/or improved viscosity modifiers. There is a need to provide analternative cellulose-containing material that can be produced fromplants and that can be used as a viscosity modifier. There is a need toprovide a simpler, less energy-intensive process of producing highviscosity cellulose-containing material from plants. Also, some of thecommonly used chemical treatment steps, such as acid or alkalihydrolysis of plant material, can take a long time. There is a need toprovide a more efficient process for extracting a usefulcellulose-containing material from plants. More particularly, there is aneed to provide a more efficient process of producing a high viscositycellulose-containing material from plants.

Most known processes of producing cellulose-containing compositions fromplants produce a composition having a particular characteristicviscosity or a narrow range of viscosities as measured at a particularconcentration in water. Thus, in order to produce a wide range ofdifferent viscosity grades of cellulose-containing material, themanufacturer has to change between different reaction systems. This mayinvolve the cleaning of a reactor in order to change reaction systemsand product. This has wastage implications, both in terms of downtimeand loss of reagents. It would be advantageous to have one reactionsystem for the breakdown of plant material that could be easilycontrolled to produce cellulose-containing material having apredetermined viscosity chosen from a wide range of possibleviscosities.

Further, it is desirable that the wide range of viscosities are a widerange of viscosities that can be achieved by the material at lowconcentrations in water, such as 1 wt % or less (unless specifiedotherwise, all references to weight (wt) herein are references to dryweight). This is not easily achieved as the chemical/biologicalbreakdown of plant material involves complex mechanisms which are notfully understood. It is also desirable to provide a process forpreparing cellulose-containing material which process is capable ofproviding and can be controlled to provide cellulose-containingcompositions of different viscosities, i.e. can be controlled to provideboth cellulose-containing compositions having a relatively highviscosity at low concentrations in water and cellulose compositionshaving a relatively low viscosity at low concentrations in water.

For many of the end uses of cellulose-containing material processed fromplants, it is necessary to decolourise the material to some extent.Decolourising cellulose-containing material produced from plants ofteninvolves additional chemical/biological treatments which increase theoverall processing time and may reduce yields. It is therefore desirableto provide an improved and efficient process for preparing suchprocessed plant material which process involves decolourising thematerial. It is also desirable to provide a process for preparingcellulose-containing material which process involves decolourising thematerial and which process can be controlled to providecellulose-containing compositions of different viscosities. There isalso a need for a process for preparing high viscositycellulose-containing material from plants which process also involvesdecolourising the material.

The present invention seeks to provide a new method of producingcellulose-containing material from plant matter which alleviates one ormore of the above problems. Further the invention seeks to provide newcompositions comprising cellulose and uses for same.

SUMMARY OF THE INVENTION

The present invention relates to a plant-derived cellulose-containingparticulate material. The cellulose-containing particles comprise plantcell wall material and are useful as rheology modifiers in water-basedsystems.

According to a first aspect of the invention there is provided aplant-derived cellulose particulate material comprising less than 30 wt% extractable glucose; and extractable xylose in an amount of at least5% of the amount of extractable xylose in the starting plant material.

According to a second aspect of the invention there is provided aprocess for preparing cellulose-containing particulate material whichhas a viscosity at a concentration of 1 dry wt % in water of at least2500 cps, the process comprising the steps of:

(i) contacting herbaceous plant material with a peroxide reagent andwater;(ii) heating the mixture from (i) to a temperature of from 30 to 110° C.and maintaining said mixture at a temperature of from 30 to 110° C.until the pH of the mixture has dropped by from about 1 to 2 pH units;and(iii) isolating the cellulose-containing particles.

Advantageously, in the second aspect of the invention, the use of aperoxide reagent to treat plant material has been found to be extremelyeffective in producing the cellulose-containing particles of the firstaspect and, in particular, high viscosity cellulose-containingparticles. The process of the invention employs the use of only onechemical reagent to break down the vegetable material, the peroxidereagent, and thus is a relatively simple, efficient process. Further,the process of the invention can be controlled relatively easily toproduce cellulose-containing particles either having a relatively lowviscosity in water or a relatively high viscosity in water. Inparticular, the viscosity of the cellulose-containing particles can becontrolled by monitoring the pH of the reaction mixture of step (ii).Also the process of the invention can be controlled to providedecolourised cellulose-containing particles without having to use anyadditional chemical/biological reagents.

A third aspect of the invention relates to the cellulose-containingparticles obtainable by the process of the invention.

In the process of the invention the plant material is broken down toparticles comprising plant cell wall material. These particles compriseplant cell wall material, retain some of the character of the plant cellwalls and, importantly, have the ability to swell with water. Theparticles have good water-holding capabilities and this propertycontributes to their usefulness as viscosity modifiers in water-basedsystems including: coatings, such as epoxy resin-based paints;polyurethane-based paints; acrylic resin-based paints; home and personalcare products such as shampoos or face creams; and concrete. They havealso been found to have good shear-thinning properties and goodmechanical properties, such as strength, and can beneficially reduce theporosity of paper compositions.

Further aspects of the invention relate to the use of thecellulose-containing particles, and compositions and emulsionscomprising the cellulose-containing particles. These areenvironmentally-friendly formulations.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph of pH and viscosity versus time for the process of theinvention described in Example 1.

FIG. 2 is a graph of viscosity versus shear rate for the epoxy paintcompositions described in Example 5.

FIG. 3 is a graph of viscosity versus shear rate for the acrylic paintcompositions described in Example 5.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise stated, references herein to cellulose-containingparticles and cellulose particulate material should be interpreted asany cellulose-containing material resulting from the processes describedherein. Such references should not be interpreted as excluding any othermaterials, rather that the particles contain or comprise cellulose.

Unless otherwise stated, references herein to extractable content of amonosaccharide other than glucose refer to the amount of the statedmonosaccharide which can be extracted through hydrolysis of an alcoholinsoluble fraction of cellulose-containing particles or celluloseparticulate material or starting plant material when contacted with 2Mtrifluoroacetic acid for 4 hours at at least 100° C.

Unless otherwise stated, references herein to extractable content ofglucose refer to the amount of glucose which can be extracted throughhydrolysis of an alcohol insoluble fraction of cellulose-containingparticles or cellulose particulate material or starting plant materialwhen contacted with 72% (w/v) sulphuric acid for 4 hours at 120° C.

Unless otherwise stated, wt % values refer to the extractable amount ofthe specified compound isolated from a known dry mass of the particulatematerial following acid hydrolysis.

Unless otherwise stated, absolute % values refer to the extractableamount of the specified compound isolated from the particulate materialfollowing acid hydrolysis as a percentage of the extractable amount ofthe specified compound isolated from the starting plant materialfollowing acid hydrolysis.

Unless otherwise stated, references herein to the starting plantmaterial are to the herbaceous plant material used in the process of thepresent invention. References to the starting plant material are also toplant material which has been homogenized to a pulp but before anychemical treatment.

Unless otherwise stated, references herein to the “peroxide process” areto the treatment of the plant material with a peroxide reagent with theapplication of heat. Unless otherwise stated, references herein to the“peroxide plus oxidant/bleach process” or the “full process” are to thetreatment of the plant material with a peroxide reagent followed bytreatment with an oxidant/bleach.

Unless otherwise stated, references herein to the viscosity of thecellulose-containing particles is the viscosity the particles at aconcentration of 1% dry weight in water as measured at 20° C. using aBrookfield viscometer with RV spindles rotated at 10 rpm. Unlessotherwise stated, references herein to “high viscosity”cellulose-containing particles are to those particles having a viscosityof at least about 2500 cps when measured according the method describedabove.

Unless otherwise stated, references herein to “low viscosity”cellulose-containing particles are to those particles having a viscosityof less than about 2500 cps, for example less than about 1000 cps, whenmeasured according the method described above.

Unless otherwise stated, the term “about” is used to provide flexibilityto a numerical range endpoint by providing that a given value may be alittle above or a little below the endpoint to allow for variation intest methods or apparatus. The degree of flexibility of this term can bedictated by the particular variable and would be within the knowledge ofthose skilled in the art to determine based on experience and theassociated description herein.

Cellulose-Containing Particles

The first aspect of the present invention provides plant-derivedcellulose particulate material comprising less than 30 wt % extractableglucose; and extractable xylose in an amount of at least 5% of theamount of extractable xylose in the starting plant material.

In the process of the invention, the plant material is broken down tocellulose-containing particles comprising plant cell wall material.Plant cell wall material comprises cellulose, hemicelluloses (such asxyloglucans, xylans mannans and glucomannans), pectins, and proteinssuch as glycoproteins. The particles can include plant cells, plant cellwalls and loose associations of plant cell wall polymeric components,which can be, for example, pieces of a gel formed from cellulose,hemicellulose, pectin and protein. It is believed that, in the processof the invention, plant cell wall breakdown occurs through partialdegradation of pectins and hemicelluloses and subsequent extraction ofpectinic and hemicellulosic monosaccharides. However, it is believedthat the process of the present invention does not degrade thecellulosic material such that some of the cell wall character/structureis retained. It is also believed that the peroxide reagent cleavescovalent bonds within the cell wall polysaccharide structure, looseningup the cell wall structure, with a result that the cellulose-containingparticles of the invention are capable of swelling with water. Thisability to swell with water contributes to the advantageousrheology-modifying properties that the particles of the presentinvention exhibit.

The cellulose-containing particles are insoluble in water. By insolublein water is meant that, at a concentration of 1 wt % (solids) or less inwater, the cellulose-containing particles are discrete particles. Adiscrete particle is one that can be observed as such using lightmicroscopy at 100× magnification. The cellulose-containing particlespreferably have a mean major dimension of from 1 to 250 μm. Theparticles can have a mean major dimension which is greater than 10 μmand up to 200 μm. Preferably they have a mean major dimension of from 10to 70 μm or from 30 to 70 μm. The mean major dimension can be measuredby light microscopy.

The particles are stained by adding a few drops of methylene blue to adilute suspension of fully hydrated particles on a slide. The particlesare viewed at 100× magnification, using a Dyno-eye camera (USB) on theeye piece of the microscope with Dynocapture 2.0 software on a computerconnected to the camera. The largest particle dimension is measuredusing image analysis.

Preferably the cellulose-containing particles contain less than 5 wt %,preferably less than 3 wt %, of microfibrillar material as measured bythe amount of material that passes through a 10 μm filter after repeatedwashing following by drying of the washings at 150° C.

The cellulose-containing particles preferably comprise cellulose in anamount of less than 60 wt %, preferably up to 59 wt %, more preferablyup to 55 wt %. Preferably the cellulose-containing particles containcellulose in an amount of at least 40 wt % or 45 wt %. In oneembodiment, the cellulose-containing particles comprise cellulose in anamount of 50 to less than 60 wt % or in an amount of less 53 to 58 wt %.

In one embodiment, the cellulose-containing particles comprise cellulosein an amount less than about 60 wt %, for example less than about 59 wt%, less than about 58 wt %, less than about 55 wt %, less than about 53wt %, less than about 50 wt %, less than about 45 wt %, less than about40 wt %.

In one embodiment, the cellulose-containing particles comprise cellulosein an amount greater than about 40 wt %, for example greater than about45 wt %, greater than about 50 wt %, greater than about 53 wt %, greaterthan about 55 wt %, greater than about 58 wt %, greater than about 59 wt%, for example up to about 60 wt %.

Preferably the cellulose-containing particles contain polysaccharidesother than cellulose in an amount of from 4 to 6 wt %.

Preferably the cellulose-containing particles contain hemicellulose inan amount of less than 2 wt % and the pectin in amount of less than 10wt %. The cellulose content and the content of the other polysaccharidesmay be measured using the following standard method: a sample of thematerial is converted into alcohol-insoluble residues and a portion ofthis is then subjected to acid hydrolysis using 2M trifluoroacetic acidfor 1 hour at 120° C. This produces a hydrolysate and a non-hydrolysablecellulosic/polysaccharide residue. The hydrolysate is dried andre-suspended in distilled water. This solution is then analysed formonosaccharide content using HPLC.

The cellulose particulate material contains extractable xylose in anamount of at least 5% of the amount of extractable xylose in thestarting plant material. Alternatively, the cellulose particulatematerial contains at least 10% of the amount of extractable xylose inthe starting plant material, for example at least 20%, at least 30%, atleast 40% extractable xylose of the amount of extractable xylose in thestarting plant material.

Alternatively, the cellulose particulate material contains at least 5%extractable xylose relative to the amount of extractable xylose in thestarting plant material. Alternatively, the cellulose particulatematerial contains at least 10% extractable xylose relative to the amountof extractable xylose in the starting plant material, for example atleast 20%, at least 30%, at least 40% extractable xylose relative to theamount of extractable xylose in the starting plant material.

Alternatively, the cellulose particulate material contains extractablexylose in an amount of at least 6% of the amount of extractable xylosein the starting plant material. Alternatively, the cellulose particulatematerial contains at least 7% of the amount of extractable xylose in thestarting plant material, for example at least 8%, at least 9%, at least10% extractable xylose of the amount of extractable xylose in thestarting plant material.

Alternatively, the cellulose particulate material contains extractablexylose in an amount of less than 0.10% of the amount of extractablexylose in the starting plant material. Alternatively, the celluloseparticulate material contains less than 9% of the amount of extractablexylose in the starting plant material, for example less than 8%, lessthan 7%, less than 6% extractable xylose of the amount of extractablexylose in the starting plant material.

Alternatively, the cellulose particulate material contains less than 70%extractable xylose relative to the amount of extractable xylose in thestarting plant material. Alternatively, the cellulose particulatematerial contains less than 60% extractable xylose relative to theamount of extractable xylose in the starting plant material, for exampleless than 55% extractable xylose relative to the amount of extractablexylose in the starting plant material.

In an alternative embodiment, the cellulose particulate material isderived from sugar beet and contains at least about 1.5 wt %, forexample at least about 1.6 wt %, at least about 1.7 wt %, at least about1.8 wt % at least about 1.9 wt %, for example about 2 wt % extractablexylose.

In an alternative embodiment, the cellulose particulate material isderived from sugar beet and contains at least about 1.5 wt %, forexample at least about 1.6 wt %, at least about 1.7 wt %, at least about1.8 wt % at least about 1.9 wt %, for example about 2 wt % extractablexylose when the amount of extractable xylose in the starting sugar beetplant material is about 20 wt %.

In an alternative embodiment, the cellulose particulate material isderived from carrot and contains at least about 0.8 wt %, for example atleast about 0.9 wt %, for example about 1.0 wt % extractable xylose.

In an alternative embodiment, the cellulose particulate material isderived from carrot and contains at least about 0.8 wt %, for example atleast about 0.9 wt %, for example about 1.0 wt % extractable xylose whenthe amount of extractable xylose in the starting carrot plant materialis about 2.0 wt %.

The cellulose particulate material contains less than 30 wt %extractable glucose. Alternatively, the cellulose particulate materialcontains less than 25 wt % extractable glucose, for example less than 20wt %, less than 19 wt %, less than 18 wt %, less than 17 wt %, less than16 wt %, less than 15 wt % extractable glucose.

In an alternative embodiment, the cellulose particulate material isderived from sugar beet and contains less than about 25 wt %, forexample less than about 20 wt %, less than about 15 wt %, for exampleabout 13 wt % extractable glucose when the amount of extractable glucosein the starting sugar beet plant material is about 7 wt %.

In an alternative embodiment, the cellulose particulate material isderived from carrot and contains less than about 25 wt %, for exampleless than about 20 wt %, for example about 19 wt % extractable glucosewhen the amount of extractable glucose in the starting carrot plantmaterial is about 11 wt %.

In one embodiment, the cellulose particulate material contains less thanabout 1 wt %, for example less than about 0.5 wt %, for example lessthan about 0.2 wt %, for example substantially no mannose. In oneembodiment, the cellulose particulate material contains less than about1 wt %, for example less than about 0.5 wt %, for example less thanabout 0.2 wt %, for example substantially no rhamnose.

In one embodiment, the cellulose particulate material may comprise oneor more polysaccharides from homogalacturonan, (1-4)-β-D-galactan,xyloglucan, (1-4)-β-D-xylan and (1-4)-β-D-arabinoxylan. In oneembodiment, the cellulose particulate material may comprise fullymethylesterified homogalacturonan, partially methylesterifiedhomogalacturonan or fully de-esterified homogalacturonan. In oneembodiment the cellulose particulate material may comprise one or moreglycoproteins. For example, in one embodiment the cellulose particulatematerial may comprise extensin. Determination of the presence of suchcomponents can be readily carried out using the CoMPP glycoarray methodas described in Møller I, Marcus S E, Haeger A, Verhertbruggen Y,Verhoef R, Schols H, Ulvskov P, Mikkelsen J D, Knox J P, Willats W.(2007) High-throughput screening of monoclonal antibodies against plantcell wall glycans by hierarchical clustering of their carbohydratemicroarray binding profiles. Glycoconj J. 25(1): 37-48.

The cellulose-containing particles preferably comprise a non-saccharide(i.e. non-carbohydrate) component which is present in an amount of 20 to50, preferably 35 to 48 wt %. This component may comprise proteins, e.g.glycoproteins.

The cellulose-containing particles can be hydrated and preferably havewater-holding capacities of 90 to 99.5 wt % water. The water-holdingcapacity is measured by dispersing the particles in water, letting themfully hydrate, then filtering them out using a 10 μm filter paper, withno pressure applied during filtering. The material collected in thefilter once the liquid has ceased to drain out is weighed, then driedusing a moisture analyser set to 150° C., and then reweighed todetermine the amount of water present.

The cellulose-containing particles can have a viscosity of up to 7500 or8000 cps. They may be high viscosity particles and have a viscosity offrom 2500, or 3000 to 7000 cps or they may be low viscosity particlesand have a viscosity of from 10 to 1000 cps.

The particles may have a viscosity of greater than about 2500 cps, forexample at least about 3000 cps, for example at least about 3200 cps forexample at least about 3500 cps, at least about 4000 cps, at least about5000 cps, at least about 5500 cps, at least about 6000 cps, at leastabout 7000 cps, at least about 7500 cps, for example up to 8000 cps.

The particles may have a viscosity of less than about 8000 cps, forexample less than about 7500 cps, less than about 7000 cps, less thanabout 6000 cps, less than about 5500 cps, less than about 5000 cps, lessthan about 4000 cps, less than about 3500 cps, less than about 3200 cps,less than about 3000 cps, for example about 2500 cps.

The particles may have a viscosity of 2500 or 3000 or 4000 cps or more,preferably the particles have a viscosity of 3500 to 5500 cps. In thisembodiment, the particles can have a water-holding capacity in the rangeof 97 to 99.5 wt % water. Preferably, they have a mean major dimensionof from 10 to 70 μm or to 100 μm and comprise cellulose in an amount of45 or 50 to less than 60 wt %. These high viscosity cellulose-containingparticles are useful as viscosity improvers for water-based systems asonly a relatively small amount is required to achieve a requiredviscosity. In addition, the viscosity of the system is increased by alarge amount at low shear rates and by a lot less at high shear rates.In other words, the cellulose-containing particles are veryshear-thinning in water-based systems and are useful as rheologymodifiers in such systems. This can be advantageous where, for example,anti-settlement of heavy additives such as pigments are required in astatic formulation, e.g. paint in a can, but where easy flow is requiredat high shear rates, for example, during application of the paint to asurface by spraying or brushing.

The cellulose-containing particles may have a viscosity of up to 2500cps, for example up to 1000 cps and preferably have a viscosity of atleast 10 or at least 100 cps. In this embodiment, the particles can havea water-holding capacity in the range of 93 to 96 wt % water.Preferably, they have a mean major dimension of from 10 to 70 μm or to100 μm and comprise cellulose in an amount of 45 or 50 to less than 60wt %. These low viscosity cellulose-containing particles are useful asviscosity improvers for water-based systems where a relatively largeamount can be added to achieve a required viscosity whilst addingmechanical strength to the substantially dried and/or cured compositematerial resulting from the water-based system. In other words, theseparticles can act as a strengthening agent for a water-based systemwithout having too strong an effect on the viscosity of the system. Inaddition, these particles can provide anticracking properties during thedrying and curing of the paint. For example, a 3% loading by dry weightin an acrylic paint can enable a coalescent content of the paint to bereduced without causing the paint to crack during drying. This isadvantageous because the coalescent is a solvent and reducing itscontent will improve the paint's environmental credentials. A 3% loadingby dry weight in an acrylic paint also increased the scrub resistance ofan acrylic paint. The low viscosity particles are also shear thinning,but start from a lower viscosity at low shear than the high viscositymaterial.

Another advantage of the cellulose-containing particles of the inventionis that in water-based formulations, the particles are quite insensitiveto pH, i.e. the viscosity does not measurably change between a pH of 2to 14, for example of 3 to 12. This is in contrast to many otherviscosity-modifying products such as hydroxyethylcellulose (HEC) thatare sensitive to pHs in this range.

Process for Preparing Cellulose-Containing Particulate Material Step (i)

Step (i) of the process of the invention comprises contacting herbaceousplant material with a peroxide reagent and water to provide a mixture ofplant material, peroxide reagent and water.

Plant Material

The plant material used in the present invention is herbaceous plantmaterial. “Herbaceous” is a well-defined botanical term that refers toannual, bi-annual or perennial vascular plants. These are furthercharacterized by their aerial stems dying after each growth season.Regrowth in subsequent seasons for bi-annual and perennial species takesplace from subterraneous organs, for example stem or root storageorgans, tubers. This is in contrast to woody species whose stems resumegrowth each season and thus form growth rings. The particular propertyof herbaceous plants of relevance to the present invention is theabundance of primary walls in their tissues. These are in particularfound in parenchymal tissues. The skilled person will be aware that noorgan from a herbaceous vascular plant is made up entirely of parenchymaor entirely of primary walls, as vascular elements with their secondarywalls are invariably also a component of all but the simplest organs.However, it will also be appreciated that plant material made up ofpolysaccharide rich primary cell walls also occurs in two groups ofplants that are not vascular plants: the mosses and the charophyceangreen algae. “Herbaceous” shall, for the purposes of this invention,also comprise biomass from these groups of plants. The plant materialused in the process of the invention therefore includes vegetables, forexample root vegetables, and fruit. Examples of root vegetables includecarrot, sugar beet (also herein referred to as “beet”) or turnip,parsnip and swede. Examples of fruit include apples, pears and grapes.The plant material may be from a potato. The plant material can bederived from one type of vegetable, for example, substantially all ofthe plant material can comprise material from one specific rootvegetable, for example, one of carrot, sugar beet, turnip, parsnip andswede. By substantially all is meant that at least 90% by dry weight ofthe vegetable material. As referred to herein, all weights are dryweight unless otherwise specified. Similarly, substantially all of theplant material can comprise material form one specific fruit, forexample, one of apples, pears or grapes. The plant material can bederived from a mixture of type of vegetables and fruit, for example,more than one of carrot, beet or turnip, parsnip, swede, apples, pears,and grapes. Preferably the plant material comprises one of or a mixtureof sugar beet and carrot. In one embodiment, the plant material used inthe process of the invention is not wood. Preferably, where the fruit orvegetable has a skin that forms greater than 3% of the weight of thefruit or vegetable, the fruit or vegetable has had the skin removed, forexample, by peeling.

Preferably the plant material has a parenchymal cell content of higherthan 30% by volume, more preferably higher than 35% by volume or higherthan 50% by volume and most preferably higher than 70% based on thetotal volume of the plant material. Parenchymal cell content isdetermined by image analysis, i.e. cutting a section of the plant,viewing the section in a microscope and measuring the areas ofparenchymal tissue. Ideally sections are taken through different partsof the plant or plant organ and these areas can then be converted into aprediction of tissue volumes. Preferably the plant material containsless than 20 wt % lignin, more preferably it contains from 1 to 10 wt %lignin, most preferably it contains from 1 to 5 wt % lignin. Lignincontent can be measured by a standard method such as the Klason method.This method uses strong acid treatment to breakdown and dissolve all theplant materials except the lignin. The lignin is defined as the weightof material that cannot be broken down by 72% sulphuric acid.

In one embodiment, the herbaceous plant material comprises less thanabout 30 wt % lignocellulose. In one embodiment, the herbaceous plantmaterial comprises less than about 20 wt % lignocellulose. In oneembodiment, the herbaceous plant material comprises less than about 15wt % lignocellulose. In one embodiment, the herbaceous plant materialcomprises less than about 10 wt % lignocellulose, for example less thanabout 9 wt % lignocellulose, less than about 8 wt % lignocellulose, lessthan about 7 wt % lignocellulose, less than about 6 wt %lignocelluloses, less than about 5 wt % lignocellulose, less than about4 wt % lignocellulose, less than about 3 wt % lignocellulose, less thanabout 2 wt % lignocellulose, less than about 1 wt % lignocellulose. Inone embodiment, the herbaceous plant material comprises substantially nolignocellulose.

In one embodiment of the present invention the herbaceous startingmaterial is a seed plant, i.e. belonging to Magnoliaphyta. In a furtherembodiment the plant is a monocotyledon, more specifically a member ofPoales, typically a cereal. The plant material may be a waste product orside-stream from agricultural production. In yet another preferredembodiment the herbaceous plant is a member of eucotyledones, morespecifically a crop plant, or a waste product or side-stream fromagricultural production. Pulps remaining after production of sugar beetor potato starch are attractive agricultural side streams useful for thepresent invention. Root crops are in general relevant raw materials. Anon-exhaustive list comprises carrot, swede, turnips, parsnips andradish. Pomace from fruit preserve, jam, juice production is anothervaluable waste product from which cellulose may be recovered by themethods disclosed in the present invention.

The plant material may be raw plant material or raw plant material thathas been heat treated and/or mechanically treated, it is preferablyWashed but is, preferably, otherwise essentially untreated. Preferably,it will not have been treated by any chemical reagents which could actto break it down. Preferably, it will not have been subjected to acid oralkali hydrolysis treatment. Preferably the plant material has beenmechanically treated, e.g. chopped/shredded so that it is in the form ofparticles having a mean major dimension of, for example, less than 10mm, preferably less than 500 μm, more preferably less than 250 μm, mostpreferably less than 200 μm. The plant material can be in the form of apulp, for example, taken from an industrial waste stream. The pulp canbe prepared from raw plant matter by washing the raw plant matter,shredding or chopping it, cooking it in water at, for example, 90 to100° C. until soft and optionally homogenising it to reduce the size ofthe insoluble particles contained therein. Alternatively, the pulp canbe prepared from raw plant matter by washing the raw plant matter,shredding or chopping it, cooking it in water in a pressure cooker untilsoft and optionally homogenising it to reduce the size of the insolubleparticles contained therein. It will be recognised that the cookingtemperature in this embodiment can exceed 100° C.

Preferably the insoluble particles of the pulp have a mean majordimension of less than 10, mm, preferably less than 500 μm, preferablyless than 250 μm, more preferably less than 200 μm. The pulp can bewashed and filtered to remove soluble by-products. In one embodiment,step (i) comprises providing a mixture of plant material, peroxidereagent and water, wherein the plant material is made up of particleshaving a mean major dimension of less than 500 μm. Step (i) can comprisepreparing pulp from raw plant material and adding peroxide reagent andwater to it. In another embodiment, step (i) can comprise providing amixture of raw plant material, peroxide reagent and water andhomogenising the mixture until the plant material is made up ofparticles having a mean major dimension of less than 500 μm.

The speed at which the process of the invention proceeds depends, inpart, upon the concentration of the reactants. Preferably, theconcentration of the plant material in the mixture of step (i) is keptto a level at which the process can be readily controlled. In oneembodiment the mixture of step (i) comprises plant material in aconcentration of from 1 to 10 wt % based on the combined amount of waterand plant material present. Preferably, this concentration is from 1 to7 wt %, more preferably from 2 to 5 wt %.

Peroxide Reagent

The process of the invention utilises a peroxide reagent to break downthe plant material and to decolourise it. Preferably the peroxidereagent is chosen from hydrogen peroxide, an organic peroxide or aninorganic peroxide. More preferably the peroxide reagent is hydrogenperoxide or an organic peroxide. Examples of suitable organic peroxidesare peroxycarboxylic acids such as peracetic acid andmeta-chloroperoxybenzoic acid and organic hydroperoxides such asbenzylperoxide. Examples of suitable inorganic peroxides include ionicperoxide salts, e.g. peroxides of the alkali and alkaline earth metalsand acid peroxides such as peroxysulfuric acid and peroxyphosphoricacid. Most preferably, the peroxide reagent is hydrogen peroxide. Theperoxide reagent is preferably present in an amount of between 5 to 40wt % based on the dry matter weight of the plant material. In oneembodiment the peroxide reagent is present in an amount of between 20 to35 wt % based on the weight of the plant material. In one embodiment,the peroxide is added as a 35% aqueous solution and the ratio ofperoxide reagent solution to dry solids content of plant material is atleast about 0.25:1 (by mass), for example at least about 0.5:1, at leastabout 0.6:1, at least about 0.7:1, at least about 0.8:1, at least about0.9:1, for example about 1:1.

In the process of the present invention, it is believed that theperoxide reagent acts to loosen the natural cell wall structure bybreaking certain bonds within the complex structure of the cell wallallowing it to hydrate (and swell) more with water and greatlyincreasing the viscosity of the plant material. This effect, the extentand speed of it, has not been observed using acid or alkali hydrolysisof vegetable material. In addition, it has been found that highviscosity cellulose-containing particles can be obtained efficiently bythe process of the present invention, with the use a single chemicaltreatment step on the plant material. Preferably the process does notcomprise any additional chemical treatments and/or any biological, e.g.enzymatic treatments.

A catalyst for catalysing the reaction of the peroxide reagent with theplant material can be added to the mixture of step (i). Examples ofcatalysts include manganese catalysts. Thus the mixture of step (i) canalso comprise a peroxide reagent catalyst. However, in one embodiment,the process of the present invention is carried out in the absence of acatalyst.

Step (ii)

Step (ii) involves heating the mixture provided in step (i). In thisstep the plant material is broken down by the peroxide reagent and alsodecolourisation of the cellulose-containing particles can occur.

In step (ii), the mixture is heated to a temperature of from 30 to 110°C., for example 30 and 100° C., and maintained at a temperature of from30 to 110° C., for example 30 and 100° C., for a period of time. Theperiod of time that the mixture is maintained within this temperaturerange can be between 1 minute and 6 hours. In one embodiment, themixture is maintained at a temperature of from 30 to 110° C., forexample 30 to 100° C., for less than 6 hours, for example less than 5hours, less than 4 hours, less than 3 hours, less than 2 hours, forexample less than 1 hour. Alternatively, the mixture is maintained at atemperature of from 30 to 110° C., for example 30 to 100° C., for atleast 1 hour, for example at least 2 hours, at least 3 hours, at least 4hours, at least 5 hours, at least 6 hours. In one embodiment, themixture is kept at a steady temperature within the range of 30 to 110°C., for example 30 to 100° C., for the period of time. In anotherembodiment, the temperature of the mixture can be varied within therange of 30 to 110° C., for example 30 to 100° C., for the period oftime, i.e., increased and/or decreased during this period of time, butstill remaining within the range of from 30 to 110° C., for example 30and 100° C. The choice of temperature(s) and the period of time themixture is kept at the temperature(s) depend on the desired viscosity ofthe cellulose-containing particles and, optionally, the desired degreeof decolourisation. Preferably the mixture is heated to a temperature offrom 70 and 100° C. and maintained at a temperature of from 70 and 100°C. for a period of time as specified above.

Viscosity

The inventors have investigated the viscosity behaviour of thecellulose-containing particles as a function of the pH of the mixture ofstep (ii) which is being held at a temperature of between 30 to 110° C.,for example 30 and 100° C., for a period of time. We refer to FIG. 1from which it can be seen that for the process carried out in Example 1,the pH of the reaction mixture varies with time and with the viscosityof the cellulose-containing particles. In one embodiment, the period oftime the mixture is maintained at a temperature of between 30 to 110°C., for example 30 and 100° C., can be determined by monitoring the pHof the reaction liquid of the reaction mixture of step (ii). The presentinventors have found that the pH of the mixture varies as the viscosityof the cellulose-containing particles varies and thus this pHmeasurement can provide an indicator of the viscosity of thecellulose-containing particles produced. It is believed that,advantageously, this pH-viscosity correlation is independent of thetemperature that the mixture of step (ii) is heated to/kept at. Thus thecorrelation can be applied to reaction systems with different heatingregimes. However, the pH-viscosity correlation may vary if the type ofplant material changes.

Thus in a preferred embodiment of the present invention, the mixture ismaintained at a temperature of between 30 to 110° C., for example 30 and100° C., until it has a predetermined pH value in order to producecellulose-containing particles having a desired viscosity. The pH valuecan be determined by a calibration run carried out under the sameconditions.

Disclosed herein is a process comprising:

-   -   (i) providing a mixture of plant material, peroxide reagent and        water;    -   (ii) heating said mixture to a temperature in the range of from        30 to 100° C. and maintaining said mixture at a temperature in        the range of from 30 to 100° C. for a period of time in order to        break down the plant material; and    -   (iii) isolating a residue comprising cellulose-containing        particles,        wherein said process comprises monitoring the pH of the mixture        during step (ii) and terminating the maintaining of the mixture        at a temperature in the range of from 30 to 110° C., for example        30 to 100° C., when the mixture reaches a predetermined pH        value.

In this embodiment said pH value can be determined from a calibrationgiving the viscosity in water of the cellulose-containing particles tobe expected as a function of pH of the reaction mixture in step (ii).Thus one example of the process comprises performing a calibrationwhereby the process is carried out several times under the sameconditions except that the period of time at which the mixture of step(ii) is maintained at a temperature of from 30 to 110° C., for example30 to 100° C., is varied. Each time the reaction mixture is sampled. ThepH is first measured and the sample then separated into an insolubleresidue containing the cellulose-containing particles and a reactionliquid component. The viscosity in water of the cellulose-containingparticles is measured and a correlation between viscosity of thecellulose-containing particles and pH of reaction mixture of step (ii)can thus be obtained.

In particular, the present inventors have found that the pH value dropsas the viscosity decreases. Therefore in the process described above,the predetermined pH is Y wherein Y=X−Δ wherein X is the pH of themixture of step (ii) at the start of the heating process and 0<Δ<4. Forcellulose-containing particles with a higher viscosity, 0<Δ<2. Inanother embodiment; 2<Δ<4, and this gives a cellulose-containingparticles with a lower viscosity. For carrot as a raw material at a 5 wt% concentration based on the water and plant material in the mixture ofstep (i): when 0<Δ<4, cellulose-containing particles having a viscosityin the range of 10 to 6800 cps can be obtained; when 0<Δ<1,cellulose-containing particles having a viscosity in the range of 5000to 3200 cps can be obtained; when 1<Δ<2, cellulose-containing particleshaving a viscosity in the range of 3200 to less than 2500 cps can beobtained; and when 2<Δ<4, cellulose-containing particles having aviscosity in the range of 2500 to less than 100 cps can be obtained.

Thus, in one embodiment, step (ii) of the process may be maintaineduntil the pH of the mixture has fallen by at least 2 pH units relativeto the starting pH, for example the pH of the mixture has fallen by atleast about 3 pH units relative to the starting pH, for example the pHof the mixture has fallen by about 4 pH units relative to the startingpH. Alternatively, step (ii) of the process may be maintained until thepH of the mixture has fallen by less than about 4 pH units relative tothe starting pH, for example the pH of the mixture has fallen by lessthan about 3 pH units relative to the starting pH, for example the pH ofthe mixture has fallen by about 2 pH units relative to the starting pH.

Thus, in one embodiment, step (ii) of the process may be maintaineduntil the pH of the mixture has fallen by less than about 2 pH unitsrelative to the starting pH, for example the pH of the mixture hasfallen by less than about 1.9 pH units relative to the starting pH, forexample the pH of the mixture has fallen by less than about 1.75 pHunits relative to the starting pH, less than about 1.5 pH units, lessthan about 1.4 pH units, less than about 1.3 pH units, less than about1.2 pH units, less than about 1.1 pH units, for example about 1 pH unit.Alternatively, step (ii) of the process may be maintained until the pHof the mixture has fallen by at least about 1 pH unit, for example atleast about 1.1 pH units, at least about 1.2 pH units, at least about1.4 pH units, at least about 1.5 pH units, at least about 1.75 pH unitsrelative to the starting pH, for example the pH of the mixture hasfallen by at least about 1.9 pH units relative to the starting pH, forexample the pH of the mixture has fallen by about 2 pH unit relative tothe starting pH. Preferably, no pH-modifying additives are added to themixture of step (i) or step (ii) during the process. By pH-modifying ismeant adjusts the pH of the mixture by a magnitude of greater than 0.5.

The present studies have involved an investigation into the viscositybehaviour of the cellulose-containing particles formed by the process ofthe invention as a function of the period of time the mixture of step(ii) is held at a temperature of between 30 to 110° C., for example 30and 0.100° C. It has been found that the viscosity of thecellulose-containing particles does not vary linearly with time. Unlessotherwise specified, as referred to herein, the viscosity of thecellulose-containing particles is the viscosity the particles at aconcentration of 1% dry weight in water as measured at 20° C. using aBrookfield viscometer with RV spindles rotated at 10 rpm.

We refer to FIG. 1 from which it can be seen that for the processcarried out in Example 1, the viscosity of the insolublecellulose-containing particles formed initially increases (from ˜1700 to4500 cps) and then reduces as the reaction progresses at temperature.The higher the temperature, the more rapidly the viscosity reaches apeak value and begins to fall. Thus, it is possible, using the processof the invention, to produce cellulose-containing compositions whichhave very different viscosities, simply by controlling the length oftime the mixture in step (ii) is held at a temperature of between 30 and100° C.

Thus, the mixture may be maintained at a temperature of between 30 to110° C., for example 30 and 100° C. for a predetermined period of timein order to produce particulate cellulose having a desired viscosity.The length of time can be determined by a calibration run carried outunder the same conditions. The calibration may change if theconcentration of the starting materials (plant material and peroxidereagent), the type of plant material or the temperature at which thereaction mixture is maintained changes.

Thus, described herein is a process which comprises:

-   -   (i) providing a mixture of plant material, peroxide reagent and        water;    -   (ii) heating said mixture to a temperature in the range of from        30 to 100° C. and maintaining said mixture at a temperature in        the range of from 30 to 100° C. a period of time in order to        break down the plant material; and    -   (iii) isolating a residue comprising cellulose-containing        particles,        wherein said period of time is chosen so as to produce        cellulose-containing particles having a desired viscosity in        water. In this process said period of time can be determined        from a calibration which gives the viscosity in water of the        cellulose-containing particles to be expected as a function of        said period of time. Thus, the process may comprise performing a        calibration whereby the process is carried out several times        under the same conditions except that the period of time at        which the mixture of step (ii) is maintained at temperature of        from 30 to 100° C. is varied. Each time the reaction mixture is        sampled. The sample is then separated into an insoluble residue        containing the cellulose-containing particles and a reaction        liquid component.

The viscosity in water of the cellulose-containing particles is measuredand this is correlated with said period of time.

In the process described herein higher viscosity materials are generallyproduced in a short reaction time, whilst lower viscosity materials aregenerally produced in a longer reaction time. This is a surprisingfinding and, as a result of this, the process to the invention can becontrolled to provide cellulose-containing particles with specificviscosity properties.

Advantageously, the process described herein can produce significantlydecolourised cellulose-containing particles as the peroxide reagent bothbreaks down the plant material and decolourises it. However, in the caseof producing the higher viscosity cellulose material, the reaction timecan be relatively short and decolourisation may not have occurred to themaximum or the required extent. It has been found that increasing ordecreasing the temperature in a series of controlled steps can help todecolourise the cellulose-containing particles while maintaining highviscosity. Thus, preferably in the production of high viscositymaterial, step (ii) may comprise heating the mixture to a temperature ofbetween 90 and 100° C. and maintaining it at this temperature for sometime, following by cooling the mixture to a temperature of between 75and 85° C. and maintaining the mixture at this temperature for the restof the period of time. Alternatively, step (ii) may comprise heating themixture to and maintaining it at a temperature of between 75 and 85° C.for a period of time then increasing the temperature to between 90 and100° C. and holding at this temperature for a period of time until thedesired degree of decolourization has been achieved.

To achieve very high viscosity cellulose-containing particles, i.e.particles with a viscosity of 6800 cps or greater, withoutdecolourisation of the particles, the mixture may only need to be heatedto a relatively low temperature for a relatively short time. Below 30°C., it is not possible to obtain high viscosity cellulose-containingparticles of the invention within a reasonable time frame, i.e. in atimeframe of hours rather than days.

To achieve high viscosity cellulose-containing particles, i.e. particleswith a viscosity of greater than 2500, for example 3000 cps or greater,with significant decolourisation of the particles and within anacceptable time frame of less than 4 hours and preferably less than 2hours, preferably the mixture should be heated to a temperature ofbetween 70 to 100° C. More preferably, the temperature is in the rangeof from 80 to 97° C., even more preferably in the range of 90 to 96° C.

To achieve low viscosity cellulose-containing particles, i.e. particleswith a viscosity of less than 2500 cps, for example 1000 cps or less,with significant decolourisation of the particles, preferably themixture should be heated to a temperature of between 90 to 100° C. andmaintained at this temperature for at least 2 hours until the desiredviscosity has been reached and maximum decolourisation has occurred.

If the mixture provided in step (i) is already hot, from the cooking ofthe vegetable material to provide a pulp, then it is possible that notmuch more additional heating of the mixture is required. If this is thecase, then the heating of step (ii) has already been partially or whollycarried out in step (i). The heating step is terminated by cooling themixture of step (ii). Preferably the mixture is cooled rapidly.

Step (ii) can also comprise a step whereby the mixture is homogenised.This can occur during heating and results in shortening the length ofstep (ii). Alternatively or additionally homogenisation can take placeafter heating. If hot peroxide is a problem for any of the equipmentbeing used then the homogenisation can be carried out after the heatingstage is completed and the material has been cooled. In one embodiment,the process of the invention involves homogenisation of the mixture ofstep (ii) either while the mixture is being maintained at temperature orafter the mixture has been cooled down or both.

In one embodiment of the process described herein, the 35% aqueousperoxide solution may be added in an amount of 0.5% by weight or less ofthe weight of the herbaceous plant material (dry content) and theperoxide treatment carried out until substantially all of the peroxidehas been consumed and the reaction then immediately terminated. In thisembodiment, a particulate cellulose material with a viscosity of atleast 2500 cps (at a 1 wt % solids concentration) is obtained.

In one embodiment of the process described herein, the 35% aqueousperoxide solution may be added in a ratio of 0.5 parts peroxide solutionor less to 1 part herbaceous plant material (dry content), for example0.25 parts peroxide solution to 1 part herbaceous plant material (drycontent) and the peroxide treatment carried out until substantially allof the peroxide has been consumed and the reaction immediatelyterminated. In this embodiment, a particulate cellulose material with aviscosity of at least 2500 cps (at a 1 wt % solids concentration) isobtained.

In one embodiment of the process described herein, the conditions forthe peroxide treatment step may be continued after substantially all ofthe peroxide has been consumed. In one embodiment, the reaction may becontinued for at least a further 30 minutes, for example at least 40minutes, or at least 60 minutes. In this embodiment, a particulatecellulose material with a viscosity of less than about 2500 cps, forexample less than about 1000 cps (at a 1 wt % solids concentration) isobtained.

Step (iii)

In step (iii) of the process of the invention a residue comprising thecellulose-containing particles is isolated. This can be achieved bywashing and filtering the product from step (ii). The washing removesany soluble breakdown products from the reaction and any excess peroxidereagent. Excess peroxide in the product of step (ii) can also be removedby the addition of a catalyst. Washing can be achieved using a number ofdifferent processes such as centrifuge filtration (continuous or batch),microfiltration, filter pressing or simple gravity driven filtration.The peroxide level and the pH can be checked. The peroxide contentshould preferably be less than 30 mg/I (as measured using a peroxideindicator stick) and pH should preferably be between 6 and 9. Optionallythe material can then be pressed or concentrated to lower the watercontent, for example to 20-50 wt % solids. This pressed cake can then bere-sized by chopping/grinding to form a powder. This powder is capableof rapid re-dispersion and re-hydration when added to water basedsystems.

Step (iv)

The process of the invention may optionally comprise a further step ofcontacting the cellulose-containing particles with an oxidant. Theoxidant may be sodium hypochlorite. The cellulose-containing particlesmay be washed with water, and optionally filtered, before beingcontacted with the oxidant. The washed and filtered cellulose-containingparticles may be reconstituted in water prior to being contacted withthe oxidant. The oxidant step may be carried out at a temperature ofabout 60° C. or less. The oxidant may be added in a ratio of about 1part oxidant to 2 parts solids in aqueous solution. The oxidant may bein the form of a 10% aqueous solution of the active oxidant. Thetemperature of the oxidant step may be maintained for at least 10minutes, for example at least 20 minutes, up to about 30 minutes. Theresultant cellulose-containing particles may be separated from theoxidant solution and washed with water until free from residual oxidant.Washing can be achieved using a number of different processes such ascentrifuge filtration (continuous or batch), microfiltration, filterpressing or simple gravity driven filtration.

Step (v)

The process of the invention may optionally comprise a further step ofhomogenizing the mixture, obtained from step (iii) or step (iv). Thestep of homogenization may take place on the filtered and dried materialfrom step (iii) or step (iv). The step of homogenization may take placeon material obtained from step (iii) or step (iv) which has beenreconstituted in water. The homogenization may be carried out until adesired particle size is obtained.

Step (vi)

The process may comprise a further step of concentrating the celluloseparticulate material or cellulose containing particles obtained to aparticular concentration. The material may be concentrated to a levelof, for example at least 5 wt % solids, for example at least about 10 wt% solids, at least about 15 wt %, at least about 20 wt %, at least about25 wt %, for example about 30 wt % solids. At levels of 15 wt % solidsand greater, the material is able to be grated, which may beadvantageous in some applications. Lower loading levels result in apaste-like consistency, which may be advantageous in other applications.

Uses of the Cellulose Particulate Materials

Cellulose and cellulose derived materials are known as additives indifferent industries due at least in part to the viscosity modifyingproperties. The present invention therefore also relates to water-based,i.e. aqueous systems or compositions comprising the cellulose-containingparticles of the present invention. Water-based systems as referred toherein include aqueous solutions and emulsions. Examples are water-basedepoxy, acrylic, polyurethane paints and water-based cosmetic systemssuch as hair shampoos, hair conditioners and face creams. Furtherexamples are food compositions. Typically in the water-based systems,the cellulose-containing particles of the invention are present in anamount of less than 10 wt %, less than 5 wt %, for example less than 3wt %, preferably less than 1 wt %, more preferably 0.05 to 0.2 or 0.5 wt%. The cellulose containing particles of the invention may be present inany of these compositions in an amount of at least 0.05 wt %, at leastabout 0.2 wt %, at least about 0.5 wt %, at least about 1 wt %, at leastabout 3 wt %, at least about 5 wt %, at least about 10 wt %. In someembodiments, the cellulose particulate material is incorporated intoaqueous compositions in an amount of less than about 2 wt %, for exampleless than about 1.5 wt %, less than about 1.2 wt %, less than about 1 wt%, less than about 0.5 wt %, less than about 0.4 wt %, less than about0.3 wt %, less than about 0.25 wt %, less than about 0.2 wt %, less thanabout 0.1 wt %, less than about 0.05 wt %, less than about 0.04 wt %,less than about 0.03 wt %, less than about 0.02 wt %, for example about0.01 wt %.

Composite Materials

The invention therefore relates to compositions and composite materialssuch as concrete and other cementitious materials. The particulatematerial described herein is particularly useful as a strengtheningagent in concrete, other cementitious materials and resin composites.

In one aspect, the invention provides a composite material comprising aresin and up to about 90 wt % plant-derived cellulose particulatematerial, wherein the plant-derived cellulose particulate materialcomprises less than 30 wt % extractable glucose; and extractable xylosein an amount of at least 5% of the amount of extractable xylose in thestarting plant material. The plant-derived cellulose particulatematerial may be present in an amount of up to about 85 wt %, for exampleup to about 80 wt %, up to about 75 wt %, up to about 70 wt %, up toabout 65 wt %.

The resin may be a thermoset resin or a thermoplastic resin. Thethermosetting resin may be polyester based or epoxide based, but it willbe understood that these are examples only and other thermosettingresins such as polyurethanes could also be used. There are manythermoplastic resins used in composite manufacture: polyolefins,polyamides, vinylic polymers, polyacetals, polysulphones,polycarbonates, polyphenylenes and polyimides. In one embodiment, theresin may be an acrylic resin. The resin may be a single resin or theresin may be a blend of more than one resin, including any of the resinsdescribed above. The composite material may further comprise one or morebinders, for example a hydrophilic binder and/or a hydrophobic binder.Such additives for resin composite materials are known in the art andneed no further discussion here.

In one aspect, the invention provides cementitious compositionscomprising the cellulose-containing particles or cellulose particulatematerial. The particulate material may be present in an amount of lessthan 10 wt %, less than 5 wt %, for example less than about 2 wt %, forexample less than about 1 wt %. The cementitious composition maycomprise any known cement. For example, the cementitious composition maycomprise a hydraulic cement such as Portland cement, which may furtherbe replaced at least in part by, for example, fly ash, slag cement orsilica fume to from a Portland cement blend. The cementitiouscomposition may comprise other additives and fillers known in the artsuch as air entrainment agents, setting retarders, setting acceleratorsand the like.

In one aspect, the invention provides concrete compositions comprisingthe cellulose-containing particles or cellulose particulate material.The particulate material may be present in an amount of less than 10 wt%, less than 5 wt %, for example less than about 2 wt %, for exampleless than about 1 wt %. The concrete composition generally comprises thecellulose particulate material described herein, a cement, and an inertaggregate material such as sand, or a mixture of sand and largerparticles such as gravel. The cement may be any type of cement asdescribed previously. Any type of filler/aggregate that is commonly usedin the building industry may be used effectively in the context of thisinvention. Examples of suitable filler/aggregates such as silica sands,calcium carbonate, dolomite, as well as lightweight aggregates such asperlites, polystyrene beads, hollow/expanded glass or ceramic spherescork, rubber, and the like, and mixture thereof. The proportion offiller/aggregate in the cement or mortar is preferably between 50% andaround 85%, more preferably between 60% and around 80%, and mostpreferably between 65% and around 75% by weight, based on the total dryingredients. It will be understood that water will subsequently be addedin order to produce the final concrete mixture to be cured.

Coatings

Cellulose particulate material is also known to be used in coatingcompositions as a viscosity modifier or for structural reinforcement toprevent, for example, cracking.

Therefore, in one aspect, the invention provides a coating compositioncomprising the cellulose-containing particles or cellulose particulatematerial. The particulate material may be present in an amount of lessthan 10 wt %, less than 5 wt %, for example less than about 2 wt %, forexample less than about 1 wt %. The coating composition may be a paintcomposition. The coating composition generally comprises a diluent orsolvent, typically water, a pigment (for example calcium carbonate,mica, silicas, talcs), a filler (which function may be provided by thepigment or a separate inert material, and one or more further additivessuch as adhesion promoters, texturizers, UV stabilisers, flatteners orbiocides as non-limiting examples. Such coating additives are typicallypresent in the composition in an amount from about 0 to about 18% byweight or up to 18 by weight and from about 1 to about 15% by weightbased on the total weight of the formulation.

Food Compositions

Cellulose particulate material is also routinely added to foodcompositions as a stabiliser, emulsifier or thickener, to modify theviscosity of the food composition. Therefore, in one aspect, theinvention provides food compositions comprising the cellulose-containingparticles or cellulose particulate material. The particulate materialmay be present in an amount of less than 10 wt %, less than 5 wt %, forexample less than about 2 wt %, for example less than about 1 wt %, lessthan about 0.5 wt %. The food composition may be an animal feedcomposition. The food composition may be a baby food composition.

These food compositions may include emulsions, beverages, sauces, soups,syrups, dressings, films, dairy and non-dairy milks and products, frozendesserts, cultured foods, bakery fillings, and bakery cream. The ediblefood products can additionally comprise diverse edible material andadditives, including proteins, fruit or vegetable juices, fruit orvegetable pulps, fruit-flavored substances, or any combination thereof.These food products can also include other edible ingredients such as,for example, mineral salts, protein sources, acidulants, sweeteners,buffering agents, pH modifiers, stabilizing salts, or a combinationthereof. Those skilled in the art will recognize that any number ofother edible components may also be added, for example, additionalflavorings, colorings, preservatives, pH buffers, nutritionalsupplements, process aids, and the like. The additional edibleingredients can be soluble or insoluble, and, if insoluble, can besuspended in the food product. Routine adjustment of the composition isfully within the capabilities of one having skill in the art and iswithin the scope and intent of the present invention. These edible foodproducts can be dry mix products (instant sauces, gravies, soups,instant cocoa drinks, etc.), low pH dairy systems (sour cream/yogurt,yogurt drinks, stabilized frozen yogurt, etc.), baked goods, and as abulking agent in non-aqueous food systems and in low moisture foodsystems.

In some embodiments, the food compositions can have enhanced storageability without the need for adjunct stabilizers (outside of theparticulate cellulose material used in the compositions). For example,some sauces that lack an adjunct stabilizer, such as xanthan gum, areshown to maintain relative viscosity for extended periods of time, whichin some instances is at least six months. The final compositions may beprocessed by heat treatment in any number of ways. These methods mayinclude, but are not limited to, pasteurization, ultra pasteurization,high temperature short time pasteurization (“HTST”), and ultra hightemperature pasteurization (“UHT”). These compositions may also beretort processed, either by rotary retort or static retort processing.Some compositions, such as juice-added or natural or artificiallyflavored soft drinks may also be cold processed. Many of these processesmay also incorporate homogenization or other high shear/high compressionmethods. There may also be co-dried compositions, which can be preparedin dry-mix form, and then conveniently reconstituted for consumption asneeded. The resulting compositions may be refrigerated and stored for acommercially acceptable period of time. In the alternative, theresulting beverages may be stored at room temperature, provided they arefilled under aseptic conditions.

Personal Care and Household Products

In accordance with the present invention, the composition may be eithera personal care product or a household care product. The personal careproduct may be a face cream, a shampoo, a conditioner, a sun screencomposition, or a moisturiser, for example. When the composition is apersonal care product, it may contain at least one active personal careingredient including, but not limited to, analgesics, anesthetics,antibiotic agents, antifungal agents, antiseptic agents, antidandruffagents, antibacterial agents, vitamins, hormones, corticosteroids,anti-inflammatory agents, vasodilators, kerolytic agents, dry-eyecompositions, wound-healing agents, anti-infection agents, as well assolvents, diluents, adjuvants and other ingredients such as water, ethylalcohol, isopropyl alcohol, propylene glycol, higher alcohols,glycerine, sorbitol, mineral oil, preservatives, surfactants,propellants, fragrances, and essential oils.

Personal care compositions include hair care, skin care, sun care, nailcare, and oral care compositions. Examples of additives in personal carecompositions include perfume, skin coolants, emollients, deodorantsother than perfumes, antiperspirant actives, moisturizing agents,cleansing agents, sunscreen active ingredients. Examples of additives inhair compositions include agents which condition and/or cleanse thehair, cleanse the hair, detangles hair, acts as styling agent,volumizing and gloss agents, color retention agent, anti-dandruff agent,hair growth promoters, hair dyes and pigments, hair perfumes, hairrelaxer, hair bleaching agent, hair moisturizer, hair oil treatmentagent, and antifrizzing agent.

The composition may be a household care composition, this household carecomposition including the cellulose particulate material and at leastone active household care ingredient. The household care activeingredient must provide some benefit to the user. The household carecomposition may comprise a laundry detergent, a fabric softener, adishwasher detergent, a surface cleaning product. The composition mayfurther retreatment compositions, bleaching agents and water softeners,including above all anionic, nonionic, cationic, amphoteric andzwitterionic surfactants, inorganic and organic, water-soluble orwater-insoluble builders and co-builders, bleaching agents, moreespecially peroxy bleaching agents, and active chlorine compounds whichare advantageously coated, bleach activators and bleach catalysts,enzymes and enzyme stabilizers, foam inhibitors, redepositioninhibitors, substances which prevent the resoiling of fabrics, so-calledsoil repellents, and typical inorganic salts, such as sulfates andorganic sulfates, such as phosphonates, optical brighteners and dyes andperfumes. In addition, the use of conventional silver protectors isrecommended for machine dishwashing detergents. These additives may beincorporated in amounts known to the skilled person.

The cellulose particulate material may be present in an emulsion. Theemulsion may comprise an aqueous phase, an oil phase and less than 10 wt% plant-derived cellulose particulate material, wherein theplant-derived cellulose particulate material comprises less than 30 wt %extractable glucose; and extractable xylose in an amount of at least 5%of the amount of extractable xylose in the starting plant material. Theemulsion may form the basis of a personal care product, a homecareproduct or a food composition as previously described.

Paper

Cellulose materials also form the basis of papers and cardboards.Additives are often added in to papers and/or cardboard to enhancephysical or chemical properties. In particular, it is desirable toreduce the porosity of a paper or cardboard in order to block permeationof gases, for example odors, fragrances or oxidants, or to blockpermeation of microbes and viral particles, when packaging food productsor cosmetic or perfumed products. Therefore, in one aspect, theinvention provides a paper composition comprising less than about 40 wt% plant-derived cellulose particulate material, wherein theplant-derived cellulose particulate material comprises less than 30 wt %extractable glucose; and extractable xylose in an amount of at least 5%of the amount of extractable xylose in the starting plant material. Thepaper composition may comprise less than about 25 wt %, for example lessthan about 20 wt %, less than about 5 wt % of the plant-derivedcellulose particulate material. Alternatively, the paper composition maycomprise more than about 5 wt %, for example more than about 10 wt %,more than about 15 wt %, more than about 20 wt %, more than about 25 wt%, more than about 30 wt %, up to about 40 wt % of the plant-derivedcellulose particulate material. The paper composition may comprise acellulosic pulp known to be useful in paper production, in combinationwith the cellulose particulate material described herein. The papercomposition may further comprise one or more additives such as inorganicfillers, optical brightening agents and pigments.

The invention is further described, but not limited to, the followingexamples.

EXAMPLES Example 1 Method for Measuring Viscosity and pH with ReactionTime for Hydrogen Peroxide Treated Root Vegetable Pulp

Fresh carrots were peeled, chopped and cooked at 90° C. for 2 hours. Thecarrots were then homogenised in the cooking liquid, using a SilversonFX homogeniser, to form a pulp with particles less than 500 microns indiameter. The concentration of the pulp was measured, using a moistureanalyser, to be 5% solids in water. The batch was then divided into anumber of 1 litre samples each contained in a polypropylene bottle withtight fitting lid. These bottles were then placed in to a water bath ofhot water regulated to 90° C. The internal temperatures of the bottleswere checked periodically. When the temperature reached 90° C., 35%hydrogen peroxide was added to each bottle in a ratio of 1 part 35%peroxide to 1 part carrot solids. The bottles were then left in thewater at 90° C. for varying lengths of time. Bottles were taken out ofthe water bath at intervals and cooled rapidly by placing into a bath ofcold water. The pH of the contents was immediately measured using a pHmeter. The contents were then poured into a coarse filter made ofhorticultural frost fleece (pore size approximately 250 microns) and theliquid allowed to drain out. The remaining solids were washed 3 timeswith clean water. Then the remaining solids were scraped out of thefilter and placed into a clean beaker. This pulp was homogenised using abench top Silverson L5M with a fine slotted collar attached in the head.Homogenisation was carried out for 15 minutes at 8000 rpm. The solidscontent of the homogenised pulp was then measured using a moistureanalyser and adjusted to 1% with fresh water. The temperature at thispoint was measured as 20° C. The viscosity of the pulp was then measuredat a concentration of 1 dry wt % in water using a Brookfield ViscometerDVII+Pro EXTRA, with RV spindle heads, run at 10 rpm. Viscosity wasrecorded in centipoise (cps). The data from these experiments was thenused to plot Viscosity as a function of time and pH as a function oftime and this plot in shown in FIG. 1.

Example 2

Preparation of high viscosity cellulose particulate material from sugarbeet 900 g of sugar beet pellets were washed and hydrated by adding themto warm water, with dirty water being drained through a sieve. Thissugar beet hydrate is placed in a large bucket in excess water andagitated before being scooped out with a colander and washed with water,to ensure that no stones/grit enter the next stage of processing

The washed sugar beet is then cooked for 3 hours at 100° C., beforebeing homogenised using a Silverson FX homogeniser fitted with initiallycoarse stator screens and moving down to the small holed emulsifierscreen (15 min process time for each screen). The solids are measuredusing an Oxford solids meter and the mixture adjusted to 2% solids byaddition of clean water.

The mix is then placed in a 25 litre glass reaction vessel and the drysolids content in the vessel is calculated. Peroxide based on ratio ofaqueous peroxide solution (at 35%) to the dry solids of 0.25:1 is addedwhen the mix is heating. The temperature is maintained for 2 hours at90° C. (once it reaches 90° C.), by which time the pH has dropped fromaround 5 to 3.5.

The reaction liquid is then removed from the vessel and washed prior tobleaching.

Bleaching is then carried out by re-suspending the washed material inclean water and placing it back in the vessel. Bleaching is performed at60° C., with a 2:1 bleach (2 parts of bleach solution with 10% activechlorine to 1 part solids, for 30 minutes).

The material is then washed and homogenised for 30 minutes on the fineslotted stator screen of the Silverson FX homogeniser.

The material is then drained through a filter and pressed betweenabsorbent cloths to a desired final solids content. Resuspension of thesolids in water at 1 wt % solids resulted in a viscosity (measured aspreviously described) of 4600 cps.

Example 3 Comparative Study: Carrots (A) Process Resulting in HighViscosity Material

Fresh carrots were cooked and homogenised to produce a pulp in waterwith 5% of carrot pulp solids. Hydrogen peroxide was then added in theratio of 1 part carrot solids to 0.35 parts of peroxide solids. Thismixture formed the reaction liquid. The liquid was then heated to 90° C.and reaction allowed to progress for 1 hr at which point the pH haddropped from 5.2 to 4.75. The resulting liquid was rapidly cooled andwashed and filtered at which point the viscosity of a 1% solids mix inwater was 3800 cps @ 10 rpm (measured on the Brookfield Viscometer withRV spindle heads, at 20° C.).

(B) Process Resulting in Low Viscosity Material

Fresh carrots were cooked and homogenised to produce a pulp in waterwith 5% of carrot pulp solids. Hydrogen peroxide was then added in theratio of 1 part carrot solids to 0.35 parts of peroxide solids. Thismixture formed the reaction liquid. The liquid was then heated to 90° C.and reaction allowed to progress for 6 hrs at which point the pH haddropped from 5 to 2.

The resulting liquid was rapidly cooled and washed and filtered at whichpoint the viscosity of a 1% solids mix in water was 600 cps @ 10 rpm(measured on the Brookfield Viscometer with RV spindle heads, at 20°C.).

Example 4 Product Analysis

Dry material from three stages of the process (start; after peroxidetreatment; after sodium hypochlorite treatment) was analysed forextractable monosaccharide/polysaccharide content. The starting plantmaterials tested were sugar beet and carrot. Comparative examples in theform of (i) cellulosic particulate material obtained from a sodiumhydroxide treatment of carrot as described in WO 2014/017911 (“Cellucomp8”); and (ii) the material from (i) also subjected to a subsequentbleach treatment (“Cellucomp 9”) and subjected to the same analysis.

The test procedure was carried out according to the standard two-stepprotocol below, which is based on separation of monosaccharides andoligosaccharides from polysaccharides by boiling the sample in an 80%alcohol solution. Monosaccharides and oligosaccharides are soluble inalcoholic solutions, whereas polysaccharides and fibre are insoluble.

The soluble components can be separated from the insoluble components byfiltration or centrifugation. The two fractions (soluble and insoluble)can then be dried and weighed to determine their concentrations.

The dried materials can then be used for analysis by HPLC, followingacid hydrolysis.

(i) Separation of Alcohol Soluble and Insoluble Components Materials

-   -   Dry samples    -   80% Ethanol    -   Compressed Nitrogen

Method

For each material sample, 50 mg was extracted three times with 5 ml of80% ethanol, by boiling the samples in capped glass tubes in 95° C.water bath for 10 min each. After each extraction, the tubes werecentrifuged at 5000×g for 5 min, and the supernatants of the threeextractions combined for sugar analysis.

The residue and supernatant are oven dried prior to acid hydrolysis.Acid hydrolysis using trifluoroacetic acid degrades pectins,hemicelluloses and highly amorphous regions of cellulose, while acidhydrolysis using 72% (w/v) sulphuric acid degrades all polysaccharideswith the exception of highly crystalline regions of cellulose.

(ii)(a) Analysis of Matrix Polysaccharides—Trifluoroacetic AcidHydrolysis

Materials

-   -   Dry samples    -   Screw cap tubes    -   2M Trifluororoacetic acid=11.4 g in 50 ml (or 3 ml 99.5% TFA and        17 ml dH₂O)    -   Compressed Nitrogen    -   Monosaccharide standards        -   Standard sugar mixture of three monosaccharides (glucose,            fructose, xylose). Each sugar is in a 10 mM stock solution            (100×). The preparation of the standards is done by            pipetting 250, 500, and 750 μl in screw cap vials and            evaporating to dryness. Proceed to hydrolysis in the same            way as with the samples.

Method Day 1

-   -   Weigh 5 mg of the alcohol insoluble fraction from step (i) in        screw cap tubes    -   Dry all the samples and monosaccharide standards (250 μl, 500        μl, 750 μl)

Day 2

-   -   In the fume hood, hydrolyse by adding 0.5 ml 2 M TFA. Flush the        vials with dry nitrogen, place the cap, and mix well. Wipe        nitrogen nozzle with ethanol tissue between samples to prevent        contamination.    -   Heat the vials at 100° C. for 4 h and mix several times during        hydrolysis.    -   Evaporate completely in centrifugal evaporator or under a        nitrogen flush with fume extraction overnight.

Day 3

-   -   Add 500 μl of propan-2-ol, mix, and evaporate.    -   Repeat    -   Resuspend the samples and standards in 200 μl of dH₂O. Mix well.    -   Centrifuge and transfer the supernatant into a new tube.    -   Filter supernatant through 0.45 μm PTFE filters prior to HPLC        analysis.        (h)(b) Analysis of Matrix Polysaccharides—Sulphuric Acid        Hydrolysis

Materials

Sulphuric acid 72% (w/v) (AR)Barium hydroxide (150 mM)Bromophenol blue (1% solution in water)0.45 μm filtersSPE reverse phase (styrene divinylbenzene); e.g. Strata-X 30 mg, 1 mlvolume.

Method

-   -   Weight accurately 4 mg of the alcohol insoluble fraction from        step (i) into a 2.0 ml screw-top microcentrifuge tube.        Alternatively use the dried residue from the matrix sugar        digestion.    -   Add 70 μl of 72% (w/v) sulphuric acid to the screw-top vial.        Mix, until solids are dispersed/dissolved.    -   Incubate in a water bath at 30° C. for 2 hours. Mix samples        every 15 minutes.    -   Add water to reduce the sulphuric acid concentration to 4.6%        (w/w)—add 1530 μl water.    -   Mix well and heat in a block heater at 121° C. for 4 hours.        Vortex every 30 minutes.    -   Cool to room temperature. (Samples may be stored in fridge for        up to 2 weeks at this point).    -   Take 300 μl into a new tube, add 1 μl of 1% bromophenol blue.        Partially neutralise by the addition of 0.8 ml 150 mM barium        hydroxide. Finish by adding barium carbonate powder. The        indicator goes blue.    -   Centrifuge to eliminate the precipitated barium sulphate (10 min        at 10000×g). Transfer supernatant to a new tube. Freeze thaw to        finish precipitation and repeat centrifugation (total volume        1050 μl).    -   Prior to HPLC, the samples (700 μl aliquot) are passed on a        reverse phase column (e.g. strata X 30 mg) and filtered through        a 0.45 μm filter.

The results of these analyses, with respect to xylose content andglucose content are shown in Table 1 below. Quantitative data can beobtained by injection of a known amount of a reference monosaccharide,for example glucose or xylose, as is routine in the art.

TABLE 1 Sample taken for TFA % xylose Sample Material Process hydrolysis(mg) Peak area xylose (mg) release Cellucomp 1 Sugar Beet Start Material4.8 30274 0.955 19.90 Cellucomp 2 Sugar Beet Peroxide Process 5.7 28800.089 1.56 Cellucomp 3 Sugar Beet Full Process 5.1 3281 0.102 2.00Cellucomp 4 Sugar Beet Full Process with extra wash 5.4 3161 0.098 1.82Cellucomp 5 Carrot Start Material 5.4 3230 0.100 1.86 Cellucomp 6 CarrotPeroxide Process 4.9 1334 0.040 0.82 Cellucomp 7 Carrot Full Process 4.71530 0.046 0.99 Cellucomp 8 Comparative Example (Carrot) NaOH + heat 5.61021 0.030 0.54 Cellucomp 9 Comparative Example (Carrot) Cellucomp 8followed by bleach 4.6 1302 0.039 0.85 Cellucomp 10 Sugar Beet (lowviscosity) Full process 4.9 1119.3 0.033 0.68 Sample taken for H2SO4 %glucose Sample Material Process hydrolysis (mg) Peak area glucose (mg)release Cellucomp 1 Sugar Beet Start Material 4.8 351 0.353 7.31Cellucomp 2 Sugar Beet Peroxide Process 5.7 1121 0.739 12.99 Cellucomp 3Sugar Beet Full Process 5.1 1830 1.098 21.57 Cellucomp 4 Sugar Beet FullProcess with extra wash 5.4 1654 1.012 18.71 Cellucomp 5 Carrot StartMaterial 5.4 858 0.605 11.26 Cellucomp 6 Carrot Peroxide Process 4.91525 0.948 19.29 Cellucomp 7 Carrot Full Process 4.7 1724 1.044 22.26Cellucomp 8 Comparative Example (Carrot) NaOH + heat 5.6 3578 1.98735.43 Cellucomp 9 Comparative Example (Carrot) Cellucomp 8 followed bybleach 4.6 2595 1.489 32.33 Cellucomp 10 Sugar Beet (low viscosity) Fullprocess 4.9 2247 1.311 26.76

Example 5 Paint Study

Two sets of paint formulations were made up (see Tables 2 and 3 below).One was made using an epoxy resin system and the other using an acrylicresin system. For each set a number of batches were made containingdifferent amounts of the primary cellulose-containing particles ofExample 3a. The weight of all additives in both the epoxy and acrylicformulations was kept constant from one batch to the next, except forwater and viscosity modifier. The weight of viscosity modifier wasvaried from one batch to another, to test the effects of differentaddition levels on the formulation viscosity. In order to keep totalformulation weight constant the weight of water added to a batch wasalso adjusted depending upon the addition level of the viscositymodifier, so that weight of water plus the viscosity modifier wasconstant from one batch to another.

The cellulose-containing particles had been pressed to reduce watercontent to 25% solids then grated using a parmesan cheese grater into acoarse powder. The ingredients of each formulation were mixed togetherat room temperature using a Dispermat paint mixer, with saw tooth bladeof 4 cm diameter rotated at 3000 rpm. Mixing was carried out for 1 hr toensure that all ingredients were fully dispersed. The mixed formulationswere allowed to stand for 1 day. Then the viscosity of each sample wasscanned over a range of shear rates using a rheometer.

For the epoxy formulation a bench mark, which was a well known Bentoniteclay rheology modifier, was used to allow comparison with the cell wallmaterial. This was mixed into the formulation at a concentration of0.25% by total formulation weight.

Similarly for the acrylic formulation a suitable bench mark was used forcomparison, which was an Acrysol associative thickener. This was mixedinto the formulation at 0.6% of total formulation weight.

TABLE 2 Material Epoxy Resin Component % g Beckopox EP 2384w/57WA 20.30101.50 Water 8.71 43.53 Cell wall material: powder 0.09 0.47 AdditolVXW-6393 Defoamer 0.40 2.00 Additol VXW-6208/60 1.00 5.00 RO-4097 RedIron Oxide 7.00 35.00 Halox SZP-391 Anti-Corrosive Pigment 4.60 23.00Barium Sulphate 9.20 46.00 Minelco Wollastonite Powder MW50 13.90 69.50Zeeosphere 400 Ceramic Microspheres 9.30 46.50 325 mesh Water GroundMica 0.70 3.50 Beckopox EP 2384w/57WA 20.30 101.50 Additol VXW-6393Defoamer 0.40 2.00 BYK 348 0.40 2.00 Cotrol AMB ammonium Benzoate (10%in Water) 3.70 18.50 100.00 500.00

A graph showing viscosity as a function of shear rate for an epoxy paintformulation with varying amounts of cellulose-containing particles addedas a viscosity modifier (here labelled A) and compared to a Bentoniteclay viscosity modifier (labelled Bentone EW) is shown in FIG. 2. It canbe seen that the use of 0.15% cellulose-containing particles generatehigher viscosities in the epoxy formulation that the Bentonite clay,particularly at low shear rates.

TABLE 3 Acrylic/low PVC formulation Material % g Water 15.57 93.42 Cellwall material: 2.3% Powder 2.33 13.98 Propylene Glycol 2.00 12.00Pat-Add AF16 0.20 1.20 Pat-Add DA 420 0.60 3.60 Pat-Add DA 202 0.40 2.40Kemira RDI-S 22.20 133.20 Neocryl XK 98 55.30 331.80 Pat Add AF 16 0.100.60 Parrmetol A 23 0.30 1.80 Pat-Add COAL 77 1.00 6.00 Total 100.00600.00

A graph showing viscosity as a function of shear rate for an acrylicpaint formulation with varying amounts of cellulose-containing particlesadded as a viscosity modifier (here labelled A) and compared to anassociative thickener acting as a viscosity modifier (Acrysol) is shownin FIG. 3. This data shows that the cellulose-containing particles aremore shear thinning than the Acrysol and is particularly effective atgiving high viscosity at low shear rates.

Example 6 Cementious Materials/Concrete

The cellulose particulate material described herein was tested for itssuitability in composite materials, particularly cementitious materialssuch as concrete and mortar.

The cellulose particulate materialwas incorporated into a mortar mix inamounts of 1 wt %, 5 wt % and 10 wt % as set out below. The mortar usedwas a decorative mortar called Enduit Beton Colore available fromMercardier.

Composition:

4.3 kg cement powder1 kg acrylic resin binder1 wt % or 5 wt % cellulose particulate material (CPM)

The indentation strength of the composite material was tested using a 2mm thick sample of material. The test used a 62.5 MPa punch with a 1 cmdiameter punch die. The results are shown in Table 4 below:

TABLE 4 Results in MPa Composition Sample 1 Sample 2 Sample 3 AverageEBC 29.5 26.5 29.5 28.5 EBC + 1% CPM 36.5 37.5 34.5 36.17 EBC + 5% CPM30.5 35 31.5 32.33 EBC + 10% CPM 29 30 26.5 28.5

This data shows that inclusion of up to 5 wt % of the celluloseparticulate material described herein led to an improvement in thestrength of the material, demonstrating that the cellulose particulatematerial is able to strengthen or reinforce inorganic compositematerials such as concrete.

Example 7 Paper Compositions

A paper composition comprising differing amounts of the celluloseparticulate material (CPM) described herein was tested for opacity andporosity.

Inclusion of the cellulose particulate material described hereindecreased porosity relative to a base paper formed from a standardcellulose. Decreasing porosity of a paper composition providesadvantages for food, cosmetic and fragrance-type packaging wherepermeation of gases, microbes and other substances is undesirable.

From the above examples, it can be seen that the cellulose particulatematerials described herein, and the processes for producing suchcellulose particulate materials find utility in many differentapplications.

1. Plant-derived cellulose particulate material comprising less than 30wt % extractable glucose; and extractable xylose in an amount of atleast 5% of the amount of extractable xylose in the starting plantmaterial.
 2. Plant-derived cellulose particulate material according toclaim 1, comprising less than 60 wt % cellulose.
 3. (canceled) 4.Plant-derived cellulose particulate material according to claim 1,wherein the plant material is derived from sugar beet.
 5. (canceled) 6.Plant-derived cellulose particulate material according to claim 1,having a non-carbohydrate content of 20 to 50% by dry weight. 7.Plant-derived cellulose particulate material according to claim 1,wherein the material has a viscosity at a concentration of 1 dry wt % inwater of greater than 2500 cps.
 8. Plant-derived cellulose particulatematerial according to claim 1, wherein the particles have a mean majordimension of from 1 to 250 μm and a mean major dimension of 10 to 100μm.
 9. Plant-derived cellulose particulate material according to claim1, wherein the particles have a water-holding capacity in the range of90 to 99.5% by weight.
 10. Plant-derived cellulose particulate materialaccording to claim 1, wherein the particles have a cellulose content offrom 40 to 60 wt %, a mean major dimension of 10 to 70 μm and aviscosity of from 4000 to 5000 cps.
 11. A process for preparingcellulose-containing particulate material which has a viscosity at aconcentration of 1 dry wt % in water of at least 2500 cps, the processcomprising the steps of: (i) contacting herbaceous plant material with aperoxide reagent and water; (ii) heating the mixture from (i) to atemperature of from 30 to 110° C. and maintaining said mixture at atemperature of from 30 to 110° C. until the pH of the mixture hasdropped by from about 1 to 2 pH units; and (iii) isolating thecellulose-containing particles.
 12. A process according to claim 11,wherein the herbaceous plant material comprises greater than 30% byvolume of parenchymal cell material.
 13. A process according to claim11, wherein the herbaceous plant material comprises less than about 10wt % lignocellulose.
 14. A process according to claim 11, wherein theherbaceous plant material is a root vegetable.
 15. (canceled)
 16. Aprocess according to claim 11, wherein step (i) includes mechanicallytreating the herbaceous plant material so that it comprises particleswith a major dimension of less than 10 mm.
 17. A process according toclaim 11, wherein step (ii) involves mechanically homogenizing themixture while the mixture is being maintained at said temperature and/orwherein step (ii) involves cooling down the mixture after the period oftime is over and then mechanically homogenizing the mixture.
 18. Aprocess according to claim 11, wherein in step (ii) the mixture isheated to a temperature of from 70 and 100° C. and maintained at atemperature of from 70 and 100° C. 19.-20. (canceled)
 21. A processaccording to claim 11, wherein the process is carried out in the absenceof an alkali or acid reagent or wherein the process is carried out inthe absence of a pH-modifying additive or in which the only chemicaltreatment used to break down the vegetable material is the peroxidechemical treatment of step (i).
 22. (canceled)
 23. A process accordingto claim 11, wherein the process comprises a further step (iv) ofcontacting the cellulose-containing particles with an oxidant. 24.-33.(canceled)
 34. A composition comprising less than 10 wt % plant-derivedcellulose particulate material, wherein the plant-derived celluloseparticulate material comprises less than 30 wt % extractable glucose;and extractable xylose in an amount of at least 5% of the amount ofextractable xylose in the starting plant material. 35.-38. (canceled)39. The composition of claim 34, wherein the composition is a coatingcomposition, further comprising a binder. 40.-41. (canceled)
 42. Thecomposition of claim 34, wherein the composition is an emulsioncomprising an aqueous phase and an oil phase. 43.-45. (canceled)